It can be explained by frequency encoding: 1. When you add the harmonics (minus the fundamental), they will align at the period of the of the fundamental frequency (ex: 4mx which corresponds to a frequency of 250hz: 2. Fundamental frequency will be the largest common denominator, looking at the smallest difference between two harmonics: peak every 4ms - period for a sound wave of 250hz - peak at every 4ms, Inferior colliculus anatomy: associated with midbrain, in the brain stem. Interaural time difference itd: azimuth: the triangle of a sound source relative to the center of the head. Interaural time differences itd: the (very small/micro seconds) difference in time between a sound arriving at one ear versus the other, because sound takes time to travel. 0. 00001ms: ex: sound comes in right ear and triggers action potential in the right cochlear nucleus, raise toward left superior olive, coincidence detector neurons in the superior olive will continue the job.